The present invention relates to a vehicle windshield for mitigating an impact on a colliding object colliding with the windshield from the front of the vehicle.
This kind of windshield is known as disclosed, for example, in Japanese Patent Laid-Open Publication No. HEI-4-19136 as a laminated safety glass which consists of an annealing glass, a resin interlayer bonded to the interior side of the annealing glass, and an impermeable film bonded to the surface on the interior side of the resin interlayer.
Another known example of such a windshield is shown in FIGS. 8A and 8B. These figures illustrate a state in which a colliding object is colliding with a windshield from the interior of the vehicle. In the figures, OUT indicates the outside of a passenger compartment and IN the inside of the passenger compartment.
FIG. 8A illustrates a colliding object 111 heading toward a windshield 112. The windshield 112 is made from a glass having two glasses 113 and 114 curved from the passenger compartment toward the vehicle outside bonded together with a plastic interlayer 115 (hereinafter referred to as a xe2x80x9claminated glassxe2x80x9d).
The laminated safety glass in HEI-4-19136 or the windshield 112 shown in FIG. 8A takes into account the safety of vehicle passengers, and mitigates the impact on the head of a passenger hitting against the laminated safety glass or the windshield 112 upon a vehicle collision. However, no consideration is given to the safety of pedestrians, that is, a colliding object from the outside of the vehicle compartment toward the laminated safety glass or the windshield 112.
In FIG. 8B, when the colliding object 111 hits on the windshield 112, the windshield 112 is partially broken, mitigating the impact of collision. However, as described above, the windshield 112 does not allow for impact from the outside of the passenger compartment. Further, the windshield 112 has a shape curved outward of the passenger compartment, that is, a so-called xe2x80x9carchxe2x80x9d shape in cross section, and is thus more unbreakable against a load from the outside of the passenger compartment than from the inside of the passenger compartment.
Further, recent years"" trends toward short-nose vehicles with passenger compartments expanded in space and slant-nose vehicles with front end portions inclined downward to reduce air resistance in high-speed travel result in increased collisions from the vehicle front toward windshields. On the other hand, with an increased rate of seatbelt wearing and the widespread adoption of airbags, importance is being attached to consideration to the safety of pedestrians in addition to the safety of vehicle passengers. In other words, it is desired to effectively mitigate the impact on a colliding object colliding with a windshield from the outside of a vehicle compartment.
According to one aspect of the present invention, there is provided a vehicle windshield which comprises: a laminated glass curved outward of a passenger compartment, the curved laminated glass being previously provided with a flexing force acting inward of the passenger compartment.
Since the force directed inward of the passenger compartment is previously provided to the windshield carved to protrude toward the vehicle outside, the windshield in its entirety is flexible toward the inside of the passenger compartment. When an object collides with the windshield from the vehicle outside, for example, the windshield can flex toward the vehicle inside, thereby absorbing the impact of the collision and mitigating impact received by the colliding object. Further, the windshield can flex toward the vehicle inside in a concave shape, thereby preventing the colliding object from being thrown out toward the side of the vehicle body after colliding with the windshield.
In a preferred form, the force is produced by applying tension to the interlayer to be disposed in the middle of the laminated glass so that the interlayer has a length larger than a free length. That is, the force is produced in the entire laminated glass by the interlayer constituting a part of the laminated glass, which eliminates the need for the addition of other extra components and can prevent increase in the number of components.
According to another aspect of the present invention, there is further provided a vehicle windshield which comprises: a plurality of sheet glasses curved outward of a vehicle; and an interlayer made from a resin material interposed between the sheet glasses for bonding the sheet glasses together, the interlayer being tensioned in every direction to have a return force.
According to a further aspect of the present invention, there is provided a method of producing a vehicle windshield, which method comprises the steps of: curving a plurality of sheet glasses into a concave shape; applying tension to an interlayer made from a resin material so that the interlayer is stretched in every direction; interposing the tensioned interlayer between the curved sheet glasses; and bonding the curved sheet glasses and the tensioned interlayer together.
In accordance with this method, the curved windshield can be easily provided with a return force.